feat(scripts): add prepare-commit-msg hook installation script

home/scripts.nix

@@ -32,6 +32,14 @@ in {
           exec $EDITOR "$1"
         '';
       })
+    (
+      pkgs.writeShellApplication {
+        name = "git-install-prepare-commit-msg";
+        text = ''
+          cp ${../scripts/prepare-commit-msg} .git/hooks/prepare-commit-msg
+        '';
+      }
+    )
     (mkScript ../scripts/yt-dlp.sh (with pkgs; [yt-dlp]))
     (mkScript ../scripts/autossh.sh (with pkgs; [autossh openssh]))
   ];

scripts/prepare-commit-msg

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+
+COMMIT_MSG_FILE=$1
+COMMIT_SOURCE=$2
+SHA1=$3
+
+if [[ -z "$COMMIT_SOURCE" ]]
+then
+  DIFF_OUTPUT=$(git diff --cached)
+  AI_CHAT_OUTPUT=$(echo "$DIFF_OUTPUT" | aichat --role %git-commit%)
+  CURRENT_MSG=$(cat "$COMMIT_MSG_FILE")
+
+  {
+    echo "$AI_CHAT_OUTPUT"
+    echo
+    echo "$CURRENT_MSG"
+  } > "$COMMIT_MSG_FILE"
+fi